Liquid seal



p 1942- A. HOLLANDER ETAL 2,295,579

LIQUID SEAL Filed July 30, 1940 2 Sheets-Sheet 2 19 bi -4 Ag Q v K4/A/0 4. years/9 35 145 0/4/0155 lV/IZRO INVENTORS 25 I ATTORNEYS Patented Sept. 15, 1942 LIQUID SEAL Aladar'llollander, Vaino A. Hoover, and Charles H. Nazro, Los Angeles, Calif., .assig'nors to Byron Jackson 00., Huntington Park, 0alif., a corporation of Delaware Application July 30, 1940, Serial No. 348,458

15 Claims.

This invention relates generally to a sealing device, and more particularly to a liquid seal for sealing the juncture of a rotating shaft anda housing through a wall of which the shaft projects. f

For certain applications, such as a submersible device embodying a housing immersed in an external liquid and containing an internal liquid and a rotating shaft extending through a wall of the housing, a liquid seal has proven to be most effective over an extended period of time in preventing admixture of the two liquids at the juncture of the shaft and housing. Particularly in submersible electric motors of the type in which the motor housing is filled with a dielectric liquid, it is of utmost importance that even minute quantities of the external liquid be prevented from entering 'the housing, especially if the external liquid is-water or other liquid having an injurious efiect on the motor windings.

As an aid in understanding the objects and purpose of the instant invention, a brief preliminary discussion of the characteristics of a liquid seal is believed to be in order. It should be borne in mind, however, that the statements made in this preliminary discussion are of a general na-' ture, and will be amplified and possibly modified to some extent during the subsequent discussion of a preferred construction embodying the in stant invention. y

The most satisfactory type of liquid seal which has been heretofore developed embodies a cup or shell secured to the shaft to rotate therewith and containing a body of sealing liquid such as mercury or other liquid of high specific gravity, and a stationary bafliesecured to the housing in concentric relation to the shaft and having a depending annular skirtextending into the body of sealing liquid. In such a seal the contact of the sealing liquid with the rotating surfaces on the shaft and cup induces rotation of the sealing 'liquid, and the centrifugal force developed in the rotating sealing liquid tends to prevent migration of the lighter weight external and internal liquids through the body of sealing liquid. However, at high ,rotativespeed such as that attained by twopole or large four-pole induction motors, certain adverse factors develop which, if not counteracted, tend to cause migration of minute particles of the external liquid through the sealing liquid and thus decrease the effectiveness of the seal. When the shaft is stationary and the pressures on oppositesides of the seal are balanced, thesurface of the sealing liquid on the inner side of the the same level asthat on the outer'side of the baffle. During rotation, however, centrifugal force tends" to throw the sealing liquid outwardly awayffrom the shaft, and, if this force is unopposed, the surface of the sealing liquid assumes a vertically inclined position at a distance from the shaft depending on various factors, such'as the linear velocity and area of the rotating surfaces contacting the sealing liquid, and the relative area of stationary surfaces contacting the sealing liquid and exertingfa frictional braking effect thereon. The annularspace thus formed between the shaft and the surface of the sealingliquid becomes filled with external liquid, thus .decreasing the thickness of and the pressure prevailing in the body of sealing liquid betweenthe external liquid and the baffle, and promoting the tendency to migration of external liquid to the outer side of the bailie and thence into the internal liquid. j

A principal object of thisinvention is to prevent the outward displacement of the sealing liquid during rotation, by the development of a force acting in opposition to the centrifugal force tending to cause the displacement. "In a prefer-red embodiment of the invention, the opposing force is developed within the body of sealing liquid by utilizing the difference in pressures prevailing in bodies of sealing liquid rotating at different speeds, to set up a secondary, or return, circulationw-ithin the sealing liquid. It has been ascertained from extensive tests that a pumping action can be established in this manner which .equals or exceeds the action ofthe centrifugal forc tending to outwardly displace the-sealing liquid, and which'can be directed in opposition to'the latter to nullify it and thus prevent outward displacement of the sealing-liquidk" A further object of the invention, istoconfine to a region remote from the shaft, the secondary circulation of sealing liquid which produces the above-mentioned pumping action, in order to avoid disturbing the stability of thesealing liquid adjacent the shaft.

A still further object of thejinvention is to confine the secondary circulation .ofsealing liquid bame, between the baflle and the shaft, assumes 55 to a region-spaced from'the surface of contact of the sealing liquid and the internal liquid, in order to avoid intermixing of the two liquldsand the resultant formation of an emulsion in the event the'internal liquid isan oil, as is often the case. V,

The manner in which theforegoing and other more specific objects are attained will be apparent from the following detailed description of one embodiment of the invention and several alternative forms thereof, reference being had to the accompanying drawings wherein:

Fig. l is a central longitudinal sectional view of one embodiment of the invention; 7

Fig. 2 is an enlarged fragmentary view of the sealing device of Fig. 1;

Fig. 3 is a transverse section on line 3-4 of Fig. 2;

Fig. 4 is a sectional view of a modification of the device of Figs. 1 and 2;-

F a. 5 is a sectional view of a still further modification; and

Fig. 6 is a fragmentary view of a still further modification.

Referring to Figs. 1 to 3, we have shown a sealing device, generally designated to, incorporated in a submersible structure comprising a shell or housing, the upperend of which is shown at H. For purpose of illustration, the housing may be considered as a submersible motor housing adapted to be submerged in a surrounding liquid and being filled with a dielectric liquid such as transil oil. The upper end of the rotor-shaft of the motor, indicated at I2, is suitably coupled to a separate shaft section If, which for convenience will be termed a seal shaft, and which extends through a central opening in the end wall I of the housing. The sealing device I. seals the juncture of the shaft l3 and the end wall It.

The lower extremity of the seal shaft is enlarged at II and is telescoped over the upper extremity of the rotor shaft I2. An annular sleeve member I! is rigidly clamped at its lower end to the enlarged portion of the shaft II in concentric relation to the shaft as by a threaded nut ll. Suitable packing I8 is interposed between the inner end of the nut and a clamping shoulder I 8 on the shaft enlargement to form a fluid-tight joint. In order to maintain the upper end of the sleeve i6 concentric with the shaft it, we have shown it as journaled in the end plate I on a ball bearing 2!. The sleeve I6 is thus mounted on the shaft If to rotate therewith about the axis of the shaft, and forms with the shaft an annular receptacle for sealing liquid such as mercury. I

. A stationary baiile, generally designated 25 extends downwardly into the receptacle through the open upper end thereof. The baiile comprises an upper cylindrical neck portion 2! rigidly secured at its upper end in fluid-tight relation to the end plate I, as by a nut 21, and a downwardly and outwardly flared portion 28, and 9. depending skirt portion 28 extending nearly to the bottom of the receptacle. The neck portion 26 extends in closely spaced concentric relation to the shaft, providing a narrow annular channel 3| communicating at its upper end with the external liquid in which the housing II is immersed, and communicating at its lower end with the portion of the mercury. receptacle lying between the baffle and the shaft. The outer wall of the neck portion 28 also has closerunning clearance with the reduced upper end 3| of the sleeve [6, providing a narrow annular channel 32 communicating at its upper end with the interior of the housing u and communicating in its lower end with the portion of the mercury receptacle on the outer side of the battle. The receptacle is normally filled with mercury up to approximately the level indicated by the dotted line a, and thus in order for any external liquid to pass. from the inner side of the baiile to the outer side thereof and into the interior of the 76 elements, and, because of the high specific gravity of the mercury, suflicient centrifugal force is developed at high speed to throw the mercury outwardly and to cause it to be displaced from the region of the shaft. It is for this reason that the upper end of the sleeve is reduced" at II to a relatively small internal diameter, to prevent the mercury from being forced upwardly out of the receptacle. In order to further'limit the upward displacement of the mercury during rotation, a lip 35 projects inwardly from the sleeve I6 adjacent its upper end to form a narrow overflow channel 36 (Fig. 2) adjacentthe outer wall of the baflie neck 26.- The portion of the receptacle between the lip 35 and the reduced upper end 3| constitutes an overflow chamber 31.

In the form of the invention shown in Figs. 1 and 2, the shaft I3 is of uniform diameter from the upper end of the baflle 25 down to a point adjacent the lower end of the batlie. It has been found that during rotation, even though the mercury is apparently in contact with at least a portion of the shaft, a capillaryfilm of external liquid may move downwardly along the shaftto thebottom of the receptacle, where there is a possibility of its being thrown radially outwardly beneath the lower end of the baffle by the pumping action of the bottom wall of the receptacle. In order to return any such particles of external liquid to the region of the shaft and to prevent their migrating to theouter side of the baffle, an

annular thimble 4 0 is secured in fluid-tight relation to the base and extends upwardly within the baflle-in telescopic relation thereto. Thus any particles of external liquid which may migrate downwardly along the shaft to the base of the receptacle are deflected upwardly along the inner wall of the thimble III to a point well above the lower end of the bafile, and as they reachthe upper end of the thimble they wi1l-be swept of! D that the only restraint imposed on the mercuryis that oflered by the sleeve l6 and the lip 35, the

position of the inner surface of the mercury during high speed rotation will be determined by the inner wall of the lip 35, and, on the inner side of the baille, it will assume approximately the position indicated by the dotted line b (Fig. 2. Such a condition is highly undesirable for several reasons, .the most important of which are i as follows:

(1) An annular space of substantial width is formed between the surface of the mercury and the shaft, which space becomes filled with externalliquid. A relatively large body of external the external liquid. When rotation ceases and the mercury assumes its normal stationary level, any sediment drawn in with the external liquid may not be expelled by the mercury but may cling to the shaft and contaminate the mercury on subsequent rotation; and

(4) Any mercury displaced into the overflow chamber above the lip 35 is ineffective in maintaining the seal, inasmuch as it has been side-- tracked out of the path followed by external or internal liquid when migrating through the seal.

We have discovered,rhowever, that it is possible to prevent this draw-down" of the mercury and its attendant ill effects, by developing a force within the body of mercury acting in opposition to the centrifugal force which causes the drawdown. During the initial starting period and before a condition of equilibrium has been established, the centrifugal force developed in the mercury manifests itself on the outer side of the baflie as anupwardly directed pressure tending to force mercury upwardly through the overflow passage 36 and into the overflow chamber until suflicient mercury has been displaced to cause the inner surface thereof to substantially eoincide with the line b of Fig. 2. Consequently, if an equal pressure were exerted downwardly in the space between the outer wall of the baflle and the sleeve 16, the displacement of the mercury over the lip 35 would be prevented and the line b would coincide with the-wall of the shaft. We have found that a downward pressure of equal or even greater magnitude than the upward pressure resulting from centrifugal force can be developed by establishing a secondary circulation I of the mercury from an upper zone in which the mercury rotates at approximately the same angular velocity asthe shaft to a lower zone in distance in a separate body of the same liquid rotating at a slower speed.

Referring to Fig. 6 of the drawings, wherein this phase of the invention isillustrated in a simpler form than in the other embodiments, it will be observed that the body of mercury in the overflow chamber 31 is bounded on three sides by surfaces on the rotating sleeve I6, and that the inner surface of themercury, designated by the line c, is in contact with the internal liquid. Because of the three rotating walls and the absence of any stationary wall contacting this body 01' mercury to exert a frictional drag thereon, it will rotate at a speed approaching that of the sleeve 15. On the other hand, the body of mercury immediately below the lip 35 rotatesat a much slower speed than the sleeve l5 because of the decreased area of rotating walls contacting the mercury and inducing rotation thereof, and because of the relatively large area of the stationary baflle 25 contacting it and retarding rotation. Consequently, at any given radial distance from the axis of the shaft, the mercury in the overflow chamber is under substantially greater pressure than the mercury in the space immediately below the lip 35, and, by establishing communication between the relatively high pressure zone in the overflow chamber and the zone below the lip 35, this relatively high pressure can be exerted downwardly in opposition to the upwardly directed pressure tending to displace the mercury from the inner side ofthe baflle. v

To this end, a plurality of vertically extending ports are provided at circumferentially spaced points in the outer margin of the lip 35 adjacent the sleeve I5, through which mercury is forced downwardly fromthe overflow chamber into the space below the lip by the greater pressure prevailing in the overflow chamber. By providing a sufllcient number of ports 45 of suitable size, the rate of discharge of mercury downwardly through the ports can be made to equal the rate at which mercury is forced through the overflow channel and into the overflow chamberduring the initial starting period, and consequently the displacement of mercury from the inner side of the baflle around the lower end thereof, and into the outer compartment between thebaflle and the sleeve Hi can be avoided altogether. The downward pressure exerted on the body of mercury inthe space below the lip 35 by thesecondary clr'cula-, tion indicated by the arrows 45 in Fig. 6 may be of s uiiicient magnitudeto equal or exceed the upward pressure developed by centrifugal force, so that, when equilibrium is established, the level 'of the mercury on the inner side of the baffle may be maintained at the point indicated atd, or may even be forced to a higher level in the annular channel 30 between the neck of the baflle and the shaft. It will be understood that the circulation around the lip as indicated by the arrows 45 continues afterequilibriumris established, and maintains the downward pressure onthe mercury in the space on'the outer side of the baille. The mercury normally filling the space between the baflle and the shaft when the latter is stationary is thus maintained in this space.

7 during rotation, and the above-mentioned draw-- down" and its attendant disadvantages are 'elim-" inated.

- Looked at in another way, the pressure intthe outer part of chamber 31 is so much greater than the pressure at the'inner part, by virtue of the centrifugal force resulting from the relatively high velocity of the mercury in the chamber 31, that by providing the ports 45, and mak ing them of suf flcient size and number, mercury can be returned from chamber 31 through the ports 45 as fast as it escapes through the pas- Y sage 36. It follows, obviously, that if mercury is returned from the chamber as fast as it enters the chamber, there can be no total change in the volumeof mercury below the lip 35 and hence no draw-down. I v I Referring again to Fig. 6, it will be observed that if the seal is filled with mercury to the level indicated at a, and if during rotation the mer-. cury is expelled from the overflow chamber through-the ports 45 as rapidly as it flows into the chamber through the overflow passage 35,

the surfaceof .the mercury in the overflow chamf ber during rotation will shift from the horizontal position indicated at a to the vertical position indicated at c. The annular space between'the surface 0 and the outer wall of the baille 25 .is

filled with internal liquid entering the seal through the channel 32, and itwill be evident that the mercury flowing upwardly through the overflow channel 35 must contact the internal liquid. This is undesirable, since irrespective of the "nature of the internal liquid, inter-mixing of the two liquids will occur, and if the internal liquid is an oil, the finely divided particles of mercury issuing from the overflow channel 36 in spray form become coated with a film of oil and form a mercury oil emulsion.

A mercury-oil emulsion is one consisting of particles of mercury surrounded with oil, as distinct from an oil-mercury emulsion which consists of particles of oil s'urrounded'by mercury. The mercury-oil emulsion is objectionable because -it is extremely diificult to break down. On the other hand, an oil-mercury emulsion, with the oil constituting the internal phase, is comparatively unstable and may be broken down by high-speed rotation, the lighter oil particles being squeezed out of the mercuryby the pressure developed by centrifugal force.

There is a. tendency to form an oil-mercury emulsion at all of the oil-mercury contact surfaces, but, as stated above, this type of emulsion is readily broken up by rotation and is not troublesome. v

However, it has been found that a mercuryoil emulsion is not only very'diflicult to break up but has entirely different characteristics from mercury alone and its formation in the overflow chamber 31 changes the position at which liquidcontact surfaces above and below the lip 35 are normally established. The formation of mercury oil emulsion in chamber 31 has a cumulative effeet, and when once started it progresses at a gradually increasing rate, inasmuch as the presence of emulsion in 'the overflow chambercreates in itself a condition favoring the formation of additional emulsion at an increased rate. Furthermore, such an emulsion eventually migrates upwardly through the annular channel 32 and escapes into the interior of the housing II, and, because of its low dielectric property, it breaks down the insulation between exposed electrical connections in the housing.

In order to avoid contact between the stream of mercury overflowing from channel 36 and the internal liquid in the overflow chamber, and to thereby prevent the formation of a mercury oil emulsion, the construction illustrated in Fig. 6 has been modified as shown inFigs. 1 and 2. It

will be observed, by referring particularly to Fig. 2, that the neck 26 of the bathe is enlarged at 50 below the lip 35, and that an auxiliary lip is provided on the sleeve l6 below the lip 35 and in the region of the enlarged section 50. In this manner an auxiliary overflow channel 52 is provided between the lip 5| and the enlarged baffle section 50, and it will be noted that the channel 52 is disposed radially outwardly of the main overflow channel 36. In this embodiment, the secondary circulation ports 45 are formed in the outer margin of the auxiliary lip 5|, as indicated in Figs. 2 and 3, and thus the circulation of mercury is upwardly through the channel 52 and into the chamber 53 between the lips 35 and 5|, and thence downwardly through the ports 45 and into the space below the lip 5|. If the seal is filled with mercury to the level indicated at a, the surface of contact between the mercury and the internal liquid in the chamber 53 will be located at the inner edge of the lip 35, as indicated by the vertical line e in Fig. 2. Hence, by

reason of the fact that the auxiliary overflow channel 52 is spaced radially outwardly of the line e, the secondary circulation indicated by the arrows 46 occurs wholly within the body of mercury and out of contact with the internal liquid, and the formation of a mercury-oil emulsion is avoided.

It will be observed that, as previously mentioned, in Fig. 6 the body of mercury above the lip 35 does not contact any stationary surface and that consequently its rotative speed will closely approach that of the sleeve It In Figs. 1 and 2, however, the isolation of the path of secondary circulation away from contact with the internal liquid has made it necessary that a portion of the inner surface of the mercury in the chamber 53 be in contact with the stationary bailie. However, in view of the relatively small area of contact with the stationary baiile in comparison with the area of contact on three sides with the rotating sleeve, the speed of rotation of the mercury in the chamber 53 of Fig. 2 is not.

In order to divert the upwardly directed stream 3 of mercury flowing through the overflow channel 52 away from the contact surface e, and to thereby avoid turbulence at that point, an overhanging shoulder 55 is formed at the upper extremity of the enlarged baflle section 50. The mercury stream is thus diverted in an outward direction toward the circulation ports 45.

In a similar manner, a deflecting shoulder 55 or other equivalent means is preferably provided in the path of the streams of mercury issuing from the lower ends of the ports 45, to divert the streams inwardly toward the baffle. Even with the deflecting surface 56, it has been found that the violence of the secondary circulation around the lip 5| may be such as to create disturbance in the body of mercury at as remote a zone as the region of the shaft I3. This should be avoided if possible, inasmuch as any disturbance of the mercury at the surface of the shaft enhances the possibility of particles of externalliquidbe-- ing sweptoff the shaft from'the previously mentioned capillary film of external liquid onthe shaft, andcarried outwardly by secondary cur rents beneath the'lower end of the bafile and into the outer compartment of the seal. In order to confine thesecondary movements of the mercury resulting from the pumping action around the lip .5|, while at the same time enabling the pressure developed thereby to be exerted againstthe mercury on the inner side of the baflle, a restricted throttling passage 6| is formed between the zone immediately below the 'lip 5| and the body ofmercury adjacent the shaft. The throttling passage'is preferably located immediately below the circulation path indicated by the arrows 43, although it will be understood that thesame effect would be produced if it were located adjacent the lower end of the baiile.

In the form of the invention shown in Figs. 1 and 2, the throttling passage 6| isformed by extending the wall of the sleeve l6 straight downwardly from the inner extremity of the deflecting surface 56, as indicated at 60, in closely spaced relationship to the outer wall of the baiiie. In this manner the secondary movements ofthe The baflle 25 is enlarged at 50 in a manner sim-- ilar to Figs. 1 and 2, and an auxiliary lip is formed on the sleeve l6 below the main lip 35 I to provide an auxiliary overflow channel 52* spaced radially outwardly of the main overflow channel 36 around the'inner edge of the main lip 35 Circulation ports-45 similar to the ports 45 of Fig. 2 extend through the auxiliary lip 5| to permit the establishment of a secondary circulation indicated by the arrows 46 thus producing a pressure opposing the pressure produced by centrifugal force tendin to displace mercury from the inner side of the baille. Thus,'instead ;of the surface of contact of the mercury and the external liquid being located at the dotted line b, V

as would be the case if the circulation Dorts 45 were omitted, the surface of contact. is maintained during rotation at approximately'the level indicated at d, at approximately the same or a higher elevation than the static level a.

In this form of the invention, the inner wall of the sleeve I6 is extended inwardly at 60 adjacent the lower portion of the baille skirt 29, to form a restricted throttling passage 6| between the sleeve and the baiile and thus protect the body of mercury on the inner side of the bailie from the disturbance created by the pumping action around the lip 52*. A separate deflecting shoulder 56 is formed below the ports 45 by an inward projection on the wall of the sleeve, to deflect the streams of mercury issuing-from the ports laterally inwardly toward the baille, and thus shorten the vertical dimension of the path of secondary circulation in the space between the battle and the sleeve and above'the throttling passage 8 I. c

The seal shown in Fig. 4 functions in the same manner as that shown in Figs. 1 and 2, and. except for the above-noted structural modifications, is substantially identical with the previously described form.

in Fig. 5 there is shown a still further modification of the seal shown in Figs. 1 and 2, this form of the invention, however, embodying only relatively minor structural modification. In this embodiment the volume of the space immediately below the auxiliary lip .il is considerably rethe overflow chamber 31', such. asto thellevel indicated at a.

The form shown inFig. 5 isotherwise stantially identical with thatshownincFigs. .1

and 2, and therefore further.descriptionthereoi is deemed unnecessary. From the foregoing description of several alternative forms ofv the invention itYwill-be apparent thatlwe have provided animproved-seaL' in which displacement of the mercury. away from the shaft during rotation is eliminated, thereby overcoming a defect inherent in seals as heretofore constructed. As a result of this improvement,-

much higher. rotative speeds are attainable be 'fore migration of external liquid around the lower end of the baiiie begins to take place. By

the elimination of draw-down. the accumulation in the seal of sediment. from the external liquid is avoided, and the entire body of mercury lying below the overflow lip when the seal is'stationary, is maintained below'the lip during rota-' tion and is therefore effective in maintaining the seal.

The elimination of the formation of a mercurycil emulsion in the overflow chamber is also of paramount importance if the seal is to be used in conjunction with submersible electrical apparatus, because of the inevitable escapeoiithe emulsion into the oil-filled housing and its eventual deposit on exposed electrical connections with disastrous results. 1

Although we have described in detail several speciflc embodiments of the invention, it will be understood that the invention is not limited to the specific constructions illustrated, but is of the full scope of the appended claims. 1 'We claim:

1. A seal for sealing the juncture ing: cup means secured to said rotatable mem-- her to rotate therewith and providing therewith an annular receptacle for sealing liquid; abatfle secured to said stationary member and.extending downwardly around said rotatable member and into said sealing liquid, said bailie dividing.

said receptacle into inner and outer compartments separated from each other at their upper ends and communicating with each other below the lower edge of said baflie; said cupmeans having a wall extending inwardly into close proximity to said baffle adjacent the upper end of said cup means and providing above said wall a'cham- 7 bar communicating with said outer compartment duced by extending the cylindrical outer wall'oi the battle skirt 29 upwardly into closer proximity to the lip 51 than is the case in Fig. 2, and by eliminating the undercut recess on theiower side of the lip 5!", thus forminga downwardly and outwardly inclined inner wall on the lip extending substantially parallel to the flared portion 28 of the baffle. j

An added safety precaution against the loss of mercury from the seal into theinterior of the enclosing housing is providedin Fig. 5 by the addition of a second lip 65 similar to the main lip .35", and a second overflowchamber 66 above the lip 55. In this manner a wider tolerance is permitted in the amount of mercury placed in the seal, since the seal will function in the same manner regardless of whether it is filled with mercury to a pointy just above the main lips 35* or up to a level indicated by the dotted line I. It is conat the inner periphery of said wall; and means forming a passageway extending through said wall and connecting the outer portion-"of said chamber with said outer compartment.

2. In a seal for sealing the juncture-of a rdtatable shaft and a stationary member, the combination of: cup means secured to said shaft to rotate therewith and providing therewith annular. receptacle for sealing liquid; a, panic secured to said stationary member and extending downwardly around said shaft and below the sur. face of said sealing liquid, said baiiie dividing said surface into a primary surface on the inner side of said baiile and a secondary surface on the outer side of said battle, and said primary surface tending to move downwardly during rotation of said sealing liquid with said shaft and cup means; and pumping means opposing downward movement of said primary surface, said pumping means comprising verticallyspaced walls on said cup means adjacent the upper end thereof and sidered preferable, however. to only partially. flll r V of a rotata-, ble member and a-stationary member, compristhrough the lowermost of said walls for continuously circulating sealing liquid from the outer portion of said chamber into the portion of said receptacle below said walls.

3. A seal for sealing the-juncture of a rotating shaft and a stationary member, comprising; cup means secured to said shaft to rotate therewith and providing a receptacle for sealing liquid; bafiie secured to said stationary member and extending downwardly around said shaft and into said sealing liquid and dividing said receptacle into inner and outer compartments; said cup means including walls in the upper portion of the cup means dividing said outer compartment into a main chamber and an auxiliary chamber thereabove, the rotating walls of said auxiliary chamber contacting a relatively small body of sealing liquid over a relatively large area and rotating said body of sealing liquid at high velocity to develop pressure therein greater than the pressure of the sealing liquid'in said main chamber; passage means connecting the outer portion of said auxiliary chamber with said main chamber for discharging sealing liquid from said auxiliary chamber to said main chamber to thereby subject the sealing liquid in said main chamber tothe pressure developed in the high velocity body of sealing liquidin said auxiliary chamber; and separate passage means for returning sealing liquid from said main chamber to said auxiliar chamber.

4. In a liquid seal of the type comprising a cup secured to a rotating member and containing sealing liquid, and a baflie secured to a stationary member and extending downwardly around said rotating member and into said sealing liquid, and in. which the sealing liquid is rotated with said cup and rotating member and tends tobe displaced'outwardly away from said rotating member by centrifugal force,'the improvement comprisingnwalls on said cup in the upper portion thereof forming va pumping chamber containing a body of sealing liquid, said walls contacting and rotating the sealing liquid in said pumping chamber at high velocity to develop a pressure therein exceeding the pressure of the main body of sealing liquid in the portion of the cup below said pumping chamber, and means forming separate, radially spaced inlet and discharge passages between said pumping chamber and said main body of sealing liquid, whereby said relatively high pressure developed in said chamber is exerted on the main body of sealing liquid in opposition to the pressure developed by centrifugal force in said main body of sealing liquid, and outward displacement of the sealing liquid away from said rotating member is prevented.

5. A liquid seal for sealing the juncture of a rotating member and a stationary member, comprising: a cupsecured to said rotating member and defining a chamber containing sealing liquid; a baflle secured to said stationary member and extending downwardly into said chamber and into said sealing liquid; said cup including an upper wall extending inwardly into relatively close proximity to said bailie and a second wall spaced below said upper wall and extending inwardly into relatively close proximity to said baffie, said second wall being disposed below the normal stationary level of said sealing liquid; the outer wall of said bailie being offset below said second wall radially outwardly of the inner periphery of said second wall; said cup including a third wall spaced below said second wall and extendingv inwardly into relatively closely spaced relation to said offset wall of, said baiile; and means forming apassageway extending vertically through the outer portion of said third wall.

6, A liquid seal for sealing the juncture of a rotating member and a stationary member, com-. prising: a cup secured to said rotating member and forming therewith a receptacle containing sealingliquid; a baiiie secured to said stationary member and extending downwardly around said rotating member and into said sealing liquid and dividing the surface thereof into a primary surface on the inner side of said baiiie and a secondary surface on the outer side of said bame, said primary surface tending to move downwardly during rotation of said sealing liquid with said rotating member and cup; and pumping means opposing said downward movement of said primary surface, comprising upper and lower ledges on said 0111) adjacent'the' upper end thereof and extending inwardly into close proximity to said bafile and defining a pumping chamber containing a body of sealing liquid, means forming a discharge passage from said chamber downwardly through said lower ledge, and walls on said baiiie andsaid lower ledge forming a passage for upward flow of sealing liquid into said chamber, said last-named passage being spaced radially inwardly of said first-named, passage and radially outwardly of the inner periphery of said upper ledge. t

7. A liquid seal for sealing the juncture of a rotatingshaft and a stationary member, comprising: a cup secured to said shaft to rotate therewith and defining with the shaft a receptacle containing sealing liquid; a ball'le secured to said stationary member and extending downwardly into said receptacle and into the sealing liquid therein',said baille including a section of relatively small outer diameter and a section therebelow of greater outer diameter than said first section and terminating at its upper end in an upwardly facing shoulder; said cup including upper and lower ribs extending radially inwardly into relatively closely spaced relation to the small and large diameter sections, respectively, of said bafile whereby said upper rib extends inwardly beyond said lower rib and overlies said shoulder; and means forming passageways for circulation of sealing liquid upwardly past the inner periphery of said lower rib and downwardly through the outer portion thereof, said upward circulation passageway being spaced radially outwardly of the inner periphery of said upper rib. I

8. A liquid sea] as set forth in claim 7, and including a projection on said bafiie between said ribs and providing'a downwardly facing shoulder overlyingsaid upward circulation passageway for deflecting the upwardly flowing sealing liquid outwardly away from the inner periphery of said upper rib.

9. A' liquid seal as set forth in claim 7, and including an inwardly extending projection on said cup providingan upwardly facing shoulder disposed beneath the path of downward circula-' tion of sealing liquid for deflecting the latter inwardly toward said baiiie. Y

10. A seal for sealing the juncture of a rotating shaft and a stationary member, comprising:

a cup secured to said shaft and providing a and baille providing a relatively narrow throttling passage between said closed circulation path and said inner compartment, whereby the sealing liquid in the latter is shielded from stray currents emanating from said secondary circulation but is subjected to the pressure developed thereby.

11. In a seal for sealing the juncture of a rotating shaft and a stationary member, the combination of: a cup secured to said shaft and providing a chamber containing sealing liquid; a bailie secured to said stationary member and extending downwardly around said shaft and into said sealing liquid, said baiile terminating in a lower edge spaced above the bottom of said chamber, and said baflie dividing said chamber into inner and outer compartments communicating with each other around the lower edge of the baflie; pumping mean in said outer compartment providing continuous secondary circulation of sealing liquid in a closed path which includes a downwardly flowing stream adjacent the wall of said cup and an upwardly flowing stream adjacent said baflle; walls on said cup and baffle providing a relatively narrow throttling passage between said closed circulation path and said inner compartment, whereby the sealing liquid in said inner compartment is protected from stray currents emanating from said secondary circulation while being subjected to the pressure developed thereby; and a projection on said cup providing an upwardly facing shoulder disposed beneath said downwardly flowing stream and deflecting the latter away from said throttling passage.

12. A liquid seal for sealing the juncture of a rotating shaft and a stationary member comprising: a cup secured to said shaft and defining therewith a receptacle containing a body of sealing liquid; a baflle secured to said stationary member and extending downwardly into said sealing liquid and dividing said receptacle into inner and outer compartments; said cup including a wall projecting into said outer compartment adjacent the upper end thereof into relatively close proximity to said baiile and defining with the latter a passageway for the flow of sealing liquid upwardly past the inner periphery of said wall; and means responsive to the presence of sealing liquid in that portion of said cup above said wall and to rotation of said shaft and cup for delivering sealing liquid from that portion of said cup above said wall into that portion of the cup below said wall.

13. Apparatus as described in claim 12, in

which said means for delivering sealing liquid from the upper portion of said cup to the lower portion thereof includesa passageway offering less resistance to fiow of sealing liquid therethrough than said first-mentioned passageway.

14. A liquid seal for sealing the juncture of a rotating shaft and a stationary member comprising: a cup secured to said shaft and defining therewith. a receptacle containing a body of sealing liquid; a baille secured to said stationary member and extending downwardly into said sealing liquid and dividing said receptacle into inner and outer compartments; said'cup including a wall projecting into said outer compartment adjacent the upper end thereof into relatively close proximity to said bafiie and defining with the latter a passageway for the flow of sealing liquid upwardly past the inner periphery of said wall; and means responsive to overflow of sealing liquid through said passageway from the lower portion to the upperportion of said cup for returning saidsealing liquid from said upper portion to said lower portion at least as rapidly.

as it flows through said passageway, whereby re-' tention of any substantially increased quantity of sealing liquid in said upper portion of said cup is precluded.

15. A seal for. sealing the juncture of a rotating shaft and a stationary member, comprising: a cup secured to said shaft and providing a chamber containing sealing liquid; a baille secured to said stationary member and extending downwardly around said shaft and into said sealing liquid anddividing said chamber into inner and outer compartments; said sealing liquid ro-' tating with said shaft and cup and tending to be displaced from said inner compartment to said outer compartment by centrifugal force; pumping means in the upper portion of said outer compartment for developing pressure opposing the outward displacement of the sealing liquid; and walls defining a relatively'narrow throttling passage between said pumping means and said inner compartment for shielding the seal ing liquid in said inner compartment from stray secondary currents emanating from said pumping means.

ALADAR HOLLANDER. VAINO A. HOOVER. CHARLES H. NAZROL 

